[PATCH V4 21/27] selftests: ublk: add ublk_io_buf_idx() for returning io buffer index

Ming Lei
2025-11-21T02:00:35Z

Since UBLK_F_PER_IO_DAEMON is added, io buffer index may depend on current
thread because the common way is to use per-pthread io_ring_ctx for issuing
ublk uring_cmd.

Add one helper for returning io buffer index, so we can hide the buffer
index implementation details for target code.

Signed-off-by: Ming Lei <ming.lei@redhat.com>
---
tools/testing/selftests/ublk/file_backed.c | 9 +++++----
tools/testing/selftests/ublk/kublk.c | 9 +++++----
tools/testing/selftests/ublk/kublk.h | 10 +++++++++-
tools/testing/selftests/ublk/null.c | 18 ++++++++++--------
tools/testing/selftests/ublk/stripe.c | 7 ++++---
5 files changed, 33 insertions(+), 20 deletions(-)

diff --git a/tools/testing/selftests/ublk/file_backed.c b/tools/testing/selftests/ublk/file_backed.c
index 9e7dd3859ea9..58ac59528b74 100644
--- a/tools/testing/selftests/ublk/file_backed.c
+++ b/tools/testing/selftests/ublk/file_backed.c
@@ -36,6 +36,7 @@ static int loop_queue_tgt_rw_io(struct ublk_thread *t, struct ublk_queue *q,
enum io_uring_op op = ublk_to_uring_op(iod, zc | auto_zc);
struct io_uring_sqe *sqe[3];
void *addr = (zc | auto_zc) ? NULL : (void *)iod->addr;
+ unsigned short buf_idx = ublk_io_buf_idx(t, q, tag);

if (!zc || auto_zc) {
ublk_io_alloc_sqes(t, sqe, 1);
@@ -47,7 +48,7 @@ static int loop_queue_tgt_rw_io(struct ublk_thread *t, struct ublk_queue *q,
iod->nr_sectors << 9,
iod->start_sector << 9);
if (auto_zc)
- sqe[0]->buf_index = tag;
+ sqe[0]->buf_index = buf_idx;
io_uring_sqe_set_flags(sqe[0], IOSQE_FIXED_FILE);
/* bit63 marks us as tgt io */
sqe[0]->user_data = build_user_data(tag, ublk_op, 0, q->q_id, 1);
@@ -56,7 +57,7 @@ static int loop_queue_tgt_rw_io(struct ublk_thread *t, struct ublk_queue *q,

ublk_io_alloc_sqes(t, sqe, 3);

- io_uring_prep_buf_register(sqe[0], q, tag, q->q_id, ublk_get_io(q, tag)->buf_index);
+ io_uring_prep_buf_register(sqe[0], q, tag, q->q_id, buf_idx);
sqe[0]->flags |= IOSQE_CQE_SKIP_SUCCESS | IOSQE_IO_HARDLINK;
sqe[0]->user_data = build_user_data(tag,
ublk_cmd_op_nr(sqe[0]->cmd_op), 0, q->q_id, 1);
@@ -64,11 +65,11 @@ static int loop_queue_tgt_rw_io(struct ublk_thread *t, struct ublk_queue *q,
io_uring_prep_rw(op, sqe[1], ublk_get_registered_fd(q, 1) /*fds[1]*/, 0,
iod->nr_sectors << 9,
iod->start_sector << 9);
- sqe[1]->buf_index = tag;
+ sqe[1]->buf_index = buf_idx;
sqe[1]->flags |= IOSQE_FIXED_FILE | IOSQE_IO_HARDLINK;
sqe[1]->user_data = build_user_data(tag, ublk_op, 0, q->q_id, 1);

- io_uring_prep_buf_unregister(sqe[2], q, tag, q->q_id, ublk_get_io(q, tag)->buf_index);
+ io_uring_prep_buf_unregister(sqe[2], q, tag, q->q_id, buf_idx);
sqe[2]->user_data = build_user_data(tag, ublk_cmd_op_nr(sqe[2]->cmd_op), 0, q->q_id, 1);

return 2;
diff --git a/tools/testing/selftests/ublk/kublk.c b/tools/testing/selftests/ublk/kublk.c
index bb8da9ff247d..1665a7865af4 100644
--- a/tools/testing/selftests/ublk/kublk.c
+++ b/tools/testing/selftests/ublk/kublk.c
@@ -579,16 +579,17 @@ static void ublk_dev_unprep(struct ublk_dev *dev)
close(dev->fds[0]);
}

-static void ublk_set_auto_buf_reg(const struct ublk_queue *q,
+static void ublk_set_auto_buf_reg(const struct ublk_thread *t,
+ const struct ublk_queue *q,
struct io_uring_sqe *sqe,
unsigned short tag)
{
struct ublk_auto_buf_reg buf = {};

if (q->tgt_ops->buf_index)
- buf.index = q->tgt_ops->buf_index(q, tag);
+ buf.index = q->tgt_ops->buf_index(t, q, tag);
else
- buf.index = q->ios[tag].buf_index;
+ buf.index = ublk_io_buf_idx(t, q, tag);

if (ublk_queue_auto_zc_fallback(q))
buf.flags = UBLK_AUTO_BUF_REG_FALLBACK;
@@ -655,7 +656,7 @@ int ublk_queue_io_cmd(struct ublk_thread *t, struct ublk_io *io)
cmd->addr = 0;

if (ublk_queue_use_auto_zc(q))
- ublk_set_auto_buf_reg(q, sqe[0], io->tag);
+ ublk_set_auto_buf_reg(t, q, sqe[0], io->tag);

user_data = build_user_data(io->tag, _IOC_NR(cmd_op), 0, q->q_id, 0);
io_uring_sqe_set_data64(sqe[0], user_data);
diff --git a/tools/testing/selftests/ublk/kublk.h b/tools/testing/selftests/ublk/kublk.h
index f5c0978f30c2..5b951ad9b03d 100644
--- a/tools/testing/selftests/ublk/kublk.h
+++ b/tools/testing/selftests/ublk/kublk.h
@@ -143,7 +143,8 @@ struct ublk_tgt_ops {
void (*usage)(const struct ublk_tgt_ops *ops);

/* return buffer index for UBLK_F_AUTO_BUF_REG */
- unsigned short (*buf_index)(const struct ublk_queue *, int tag);
+ unsigned short (*buf_index)(const struct ublk_thread *t,
+ const struct ublk_queue *, int tag);
};

struct ublk_tgt {
@@ -351,6 +352,13 @@ static inline void ublk_set_sqe_cmd_op(struct io_uring_sqe *sqe, __u32 cmd_op)
addr[1] = 0;
}

+static inline unsigned short ublk_io_buf_idx(const struct ublk_thread *t,
+ const struct ublk_queue *q,
+ unsigned tag)
+{
+ return q->ios[tag].buf_index;
+}
+
static inline struct ublk_io *ublk_get_io(struct ublk_queue *q, unsigned tag)
{
return &q->ios[tag];
diff --git a/tools/testing/selftests/ublk/null.c b/tools/testing/selftests/ublk/null.c
index 280043f6b689..819f72ac2da9 100644
--- a/tools/testing/selftests/ublk/null.c
+++ b/tools/testing/selftests/ublk/null.c
@@ -43,12 +43,12 @@ static int ublk_null_tgt_init(const struct dev_ctx *ctx, struct ublk_dev *dev)
}

static void __setup_nop_io(int tag, const struct ublksrv_io_desc *iod,
- struct io_uring_sqe *sqe, int q_id)
+ struct io_uring_sqe *sqe, int q_id, unsigned buf_idx)
{
unsigned ublk_op = ublksrv_get_op(iod);

io_uring_prep_nop(sqe);
- sqe->buf_index = tag;
+ sqe->buf_index = buf_idx;
sqe->flags |= IOSQE_FIXED_FILE;
sqe->rw_flags = IORING_NOP_FIXED_BUFFER | IORING_NOP_INJECT_RESULT;
sqe->len = iod->nr_sectors << 9; /* injected result */
@@ -60,18 +60,19 @@ static int null_queue_zc_io(struct ublk_thread *t, struct ublk_queue *q,
{
const struct ublksrv_io_desc *iod = ublk_get_iod(q, tag);
struct io_uring_sqe *sqe[3];
+ unsigned short buf_idx = ublk_io_buf_idx(t, q, tag);

ublk_io_alloc_sqes(t, sqe, 3);

- io_uring_prep_buf_register(sqe[0], q, tag, q->q_id, ublk_get_io(q, tag)->buf_index);
+ io_uring_prep_buf_register(sqe[0], q, tag, q->q_id, buf_idx);
sqe[0]->user_data = build_user_data(tag,
ublk_cmd_op_nr(sqe[0]->cmd_op), 0, q->q_id, 1);
sqe[0]->flags |= IOSQE_CQE_SKIP_SUCCESS | IOSQE_IO_HARDLINK;

- __setup_nop_io(tag, iod, sqe[1], q->q_id);
+ __setup_nop_io(tag, iod, sqe[1], q->q_id, buf_idx);
sqe[1]->flags |= IOSQE_IO_HARDLINK;

- io_uring_prep_buf_unregister(sqe[2], q, tag, q->q_id, ublk_get_io(q, tag)->buf_index);
+ io_uring_prep_buf_unregister(sqe[2], q, tag, q->q_id, buf_idx);
sqe[2]->user_data = build_user_data(tag, ublk_cmd_op_nr(sqe[2]->cmd_op), 0, q->q_id, 1);

// buf register is marked as IOSQE_CQE_SKIP_SUCCESS
@@ -85,7 +86,7 @@ static int null_queue_auto_zc_io(struct ublk_thread *t, struct ublk_queue *q,
struct io_uring_sqe *sqe[1];

ublk_io_alloc_sqes(t, sqe, 1);
- __setup_nop_io(tag, iod, sqe[0], q->q_id);
+ __setup_nop_io(tag, iod, sqe[0], q->q_id, ublk_io_buf_idx(t, q, tag));
return 1;
}

@@ -136,11 +137,12 @@ static int ublk_null_queue_io(struct ublk_thread *t, struct ublk_queue *q,
* return invalid buffer index for triggering auto buffer register failure,
* then UBLK_IO_RES_NEED_REG_BUF handling is covered
*/
-static unsigned short ublk_null_buf_index(const struct ublk_queue *q, int tag)
+static unsigned short ublk_null_buf_index(const struct ublk_thread *t,
+ const struct ublk_queue *q, int tag)
{
if (ublk_queue_auto_zc_fallback(q))
return (unsigned short)-1;
- return q->ios[tag].buf_index;
+ return ublk_io_buf_idx(t, q, tag);
}

const struct ublk_tgt_ops null_tgt_ops = {
diff --git a/tools/testing/selftests/ublk/stripe.c b/tools/testing/selftests/ublk/stripe.c
index 50874858a829..db281a879877 100644
--- a/tools/testing/selftests/ublk/stripe.c
+++ b/tools/testing/selftests/ublk/stripe.c
@@ -135,6 +135,7 @@ static int stripe_queue_tgt_rw_io(struct ublk_thread *t, struct ublk_queue *q,
struct ublk_io *io = ublk_get_io(q, tag);
int i, extra = zc ? 2 : 0;
void *base = (zc | auto_zc) ? NULL : (void *)iod->addr;
+ unsigned short buf_idx = ublk_io_buf_idx(t, q, tag);

io->private_data = s;
calculate_stripe_array(conf, iod, s, base);
@@ -142,7 +143,7 @@ static int stripe_queue_tgt_rw_io(struct ublk_thread *t, struct ublk_queue *q,
ublk_io_alloc_sqes(t, sqe, s->nr + extra);

if (zc) {
- io_uring_prep_buf_register(sqe[0], q, tag, q->q_id, io->buf_index);
+ io_uring_prep_buf_register(sqe[0], q, tag, q->q_id, buf_idx);
sqe[0]->flags |= IOSQE_CQE_SKIP_SUCCESS | IOSQE_IO_HARDLINK;
sqe[0]->user_data = build_user_data(tag,
ublk_cmd_op_nr(sqe[0]->cmd_op), 0, q->q_id, 1);
@@ -158,7 +159,7 @@ static int stripe_queue_tgt_rw_io(struct ublk_thread *t, struct ublk_queue *q,
t->start << 9);
io_uring_sqe_set_flags(sqe[i], IOSQE_FIXED_FILE);
if (auto_zc || zc) {
- sqe[i]->buf_index = tag;
+ sqe[i]->buf_index = buf_idx;
if (zc)
sqe[i]->flags |= IOSQE_IO_HARDLINK;
}
@@ -168,7 +169,7 @@ static int stripe_queue_tgt_rw_io(struct ublk_thread *t, struct ublk_queue *q,
if (zc) {
struct io_uring_sqe *unreg = sqe[s->nr + 1];

- io_uring_prep_buf_unregister(unreg, q, tag, q->q_id, io->buf_index);
+ io_uring_prep_buf_unregister(unreg, q, tag, q->q_id, buf_idx);
unreg->user_data = build_user_data(
tag, ublk_cmd_op_nr(unreg->cmd_op), 0, q->q_id, 1);
}
--
2.47.0